The Protein Interactions Expert


Yeast cultures

ULTImate RNA Y3H (RNA yeast three-hybrid) for RNA bait screening.

Derived from our ULTImate Y2H technology, it allows to screen highly complex domain-based libraries to identify protein partners of any short RNA.

If you want more details on this service, please CONTACT US.


  • Identify and characterize RNA-protein interactions

Molecules Tested

  • Short RNA

How does it work?

ULTImate RNA Y3H is based on ULTImate Y2H, with modifications to use a small RNA as a bait. It consists of the detection of ‘bait-prey’ interactions thanks to the reconstitution of a full transcription factor from DNA Binding Domain and Activation Domain moieties. In the RNA Y3H approach, three hybrid molecules are used:

  • A hybrid protein containing a DNA Binding Domain (DBD) fused to a RNA Binding Domain (RBD)
  • A hybrid protein containing a transcriptional Activation Domain (AD) fused to a ‘prey’ protein fragment from the library
  • A hybrid RNA molecule consisting of two RNA fragments, the RNA anchor interacting with RBD and the RNA bait.

Upon interaction of the RNA bait with the prey, the gap between the DBD and the AD is bridged, enabling the transcription of the reporter gene in yeast cells. The DNA of the positive clones is then sequenced and analyzed to identify the protein partners.

For more details about our screening technology and libraries, please refer to ULTImate Y2H and ULTImate Libraries.


  • Fast and exhaustive screening thanks to Hybrigenics patented cell-to-cell mating protocol
  • Detection of even weak interactions and interactions with proteins whose transcripts are rare
  • Full sophisticated bioinformatics analysis of the results including confidence scores
  • Up to 380 positive clones analyzed (5’ and 3’ sequences)
  • Scientific assistance for the best outcome of your project


The results of your ULTImate RNA Y3H screen come fully analyzed to help you focus on the most relevant interactions. The deliverables include the list of identified protein partners, the experimental interaction domain on each protein and a confidence score. Please click here for a detailed presentation.

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